Bottom Line:
One way that behaviour can evolve is to have a genetic basis.The result was not due to lack of power, and indicates that there was no association between these behaviours and variation in the candidate genes tested in this population.These findings provide important data to facilitate representative future meta-analyses on candidate personality genes.

Affiliation: Department of Animal and Plant Sciences, University of Sheffield, Sheffield, United Kingdom.

ABSTRACTConsistency of between-individual differences in behaviour or personality is a phenomenon in populations that can have ecological consequences and evolutionary potential. One way that behaviour can evolve is to have a genetic basis. Identifying the molecular genetic basis of personality could therefore provide insight into how and why such variation is maintained, particularly in natural populations. Previously identified candidate genes for personality in birds include the dopamine receptor D4 (DRD4), and serotonin transporter (SERT). Studies of wild bird populations have shown that exploratory and bold behaviours are associated with polymorphisms in both DRD4 and SERT. Here we tested for polymorphisms in DRD4 and SERT in the Seychelles warbler (Acrocephalus sechellensis) population on Cousin Island, Seychelles, and then investigated correlations between personality and polymorphisms in these genes. We found no genetic variation in DRD4, but identified four polymorphisms in SERT that clustered into five haplotypes. There was no correlation between bold or exploratory behaviours and SERT polymorphisms/haplotypes. The result was not due to lack of power, and indicates that there was no association between these behaviours and variation in the candidate genes tested in this population. These findings provide important data to facilitate representative future meta-analyses on candidate personality genes.

pone.0138439.g005: The coefficients and associated 95% confidence intervals of the additive haplotype models for bold behaviour.The models are relative to individuals with no copies of the haplotype, subordinate is relative to dominant, male is relative to female.

Mentions:
Overall, there was no effect of haplotype on bold and exploratory behaviours in the overdominant and additive models (Figs 2–5, accompanying LRT values can be found in S6 and S7 Tables). Similarly no SNP effect was seen in the overdominant and additive models for bold and exploratory behaviour (S2–S5 Figs, accompanying LRT values can be found in S6 and S7 Tables). There was a positive correlation with age for exploratory behaviour and bold behaviour in all models (haplotype models Figs 2–5; SNP models S2–S5 Figs). Dominant individuals were bolder than subordinates in the additive and overdominant models for haplotypes one and two. Individuals also became bolder with increasing assay number in the overdominant model for haplotype one (Fig 3).

pone.0138439.g005: The coefficients and associated 95% confidence intervals of the additive haplotype models for bold behaviour.The models are relative to individuals with no copies of the haplotype, subordinate is relative to dominant, male is relative to female.

Mentions:
Overall, there was no effect of haplotype on bold and exploratory behaviours in the overdominant and additive models (Figs 2–5, accompanying LRT values can be found in S6 and S7 Tables). Similarly no SNP effect was seen in the overdominant and additive models for bold and exploratory behaviour (S2–S5 Figs, accompanying LRT values can be found in S6 and S7 Tables). There was a positive correlation with age for exploratory behaviour and bold behaviour in all models (haplotype models Figs 2–5; SNP models S2–S5 Figs). Dominant individuals were bolder than subordinates in the additive and overdominant models for haplotypes one and two. Individuals also became bolder with increasing assay number in the overdominant model for haplotype one (Fig 3).

Bottom Line:
One way that behaviour can evolve is to have a genetic basis.The result was not due to lack of power, and indicates that there was no association between these behaviours and variation in the candidate genes tested in this population.These findings provide important data to facilitate representative future meta-analyses on candidate personality genes.

Affiliation:
Department of Animal and Plant Sciences, University of Sheffield, Sheffield, United Kingdom.

ABSTRACTConsistency of between-individual differences in behaviour or personality is a phenomenon in populations that can have ecological consequences and evolutionary potential. One way that behaviour can evolve is to have a genetic basis. Identifying the molecular genetic basis of personality could therefore provide insight into how and why such variation is maintained, particularly in natural populations. Previously identified candidate genes for personality in birds include the dopamine receptor D4 (DRD4), and serotonin transporter (SERT). Studies of wild bird populations have shown that exploratory and bold behaviours are associated with polymorphisms in both DRD4 and SERT. Here we tested for polymorphisms in DRD4 and SERT in the Seychelles warbler (Acrocephalus sechellensis) population on Cousin Island, Seychelles, and then investigated correlations between personality and polymorphisms in these genes. We found no genetic variation in DRD4, but identified four polymorphisms in SERT that clustered into five haplotypes. There was no correlation between bold or exploratory behaviours and SERT polymorphisms/haplotypes. The result was not due to lack of power, and indicates that there was no association between these behaviours and variation in the candidate genes tested in this population. These findings provide important data to facilitate representative future meta-analyses on candidate personality genes.